Field of the Invention
The present invention relates to an apparatus and method for optical interferometric measurements of in-plane and out-of-plane ultrasonic surface displacements in materials. The apparatus of the present invention provides for automatic alignment of the interferometric system and for simultaneous measurements of in-plane and out-of-plane displacements. These features eliminate time-consuming alignment procedures required by conventional apparatus. The attenuation of the displacements can be obtained directly, because the in-plane and out-of-plane components of the displacement amplitude are separately measured.